test(api): add /prices-history real API integration test

tests/prices_history_integration_tests.rs

@@ -0,0 +1,46 @@
+// Real API integration tests for /prices-history.
+//
+// These tests hit Polymarket's live HTTP API and are ignored by default.
+//
+// Run with:
+//   cargo test --all-features --test prices_history_integration_tests -- --ignored --nocapture --test-threads=1
+
+use polyfill_rs::{ClobClient, PricesHistoryInterval};
+
+const HOST: &str = "https://clob.polymarket.com";
+
+#[tokio::test(flavor = "multi_thread")]
+#[ignore]
+async fn test_real_api_get_prices_history_interval_parses() {
+    let client = ClobClient::new(HOST);
+    let markets = client
+        .get_sampling_markets(None)
+        .await
+        .expect("failed to fetch sampling markets");
+
+    let token_ids: Vec<String> = markets
+        .data
+        .iter()
+        .filter(|m| m.active && !m.closed)
+        .filter_map(|m| m.tokens.first().map(|t| t.token_id.clone()))
+        .take(20)
+        .collect();
+
+    assert!(!token_ids.is_empty(), "no active token IDs found");
+
+    // The API sometimes returns empty history for some markets; try a few and
+    // assert at least one returns a non-empty series (verifies endpoint semantics).
+    for token_id in token_ids {
+        let response = client
+            .get_prices_history_interval(&token_id, PricesHistoryInterval::OneDay, Some(5))
+            .await
+            .expect("failed to fetch prices history");
+
+        if !response.history.is_empty() {
+            return;
+        }
+    }
+
+    panic!("expected at least one active market to return non-empty price history");
+}
+